var DoubleUtils = function () {
    return this;
};
DoubleUtils.prototype = {
    constructor: DoubleUtils,
    add: function(arg1,arg2){
        var r1,r2,m;
        try{r1=arg1.toString().split(".")[1].length}catch(e){r1=0}
        try{r2=arg2.toString().split(".")[1].length}catch(e){r2=0}
        m=Math.pow(10,Math.max(r1,r2));
        return (arg1*m+arg2*m)/m;
    },

    sub: function(arg1,arg2){
        var r1,r2,m,n;
        try{r1=arg1.toString().split(".")[1].length}catch(e){r1=0}
        try{r2=arg2.toString().split(".")[1].length}catch(e){r2=0}
        m=Math.pow(10,Math.max(r1,r2));
        //动态控制精度长度
        n=(r1>=r2)?r1:r2;
        return ((arg1*m-arg2*m)/m);  //.toFixed(n)
    },

    mul: function(arg1,arg2)   {
        var m=0,s1=arg1.toString(),s2=arg2.toString();
        try{m+=s1.split(".")[1].length}catch(e){}
        try{m+=s2.split(".")[1].length}catch(e){}
        return Number(s1.replace(".",""))*Number(s2.replace(".",""))/Math.pow(10,m);
    },

    div: function(arg1,arg2){
        var t1=0,t2=0,r1,r2;
        try{t1=arg1.toString().split(".")[1].length}catch(e){}
        try{t2=arg2.toString().split(".")[1].length}catch(e){}
        r1=Number(arg1.toString().replace(".",""));
        r2=Number(arg2.toString().replace(".",""));
        return (r1/r2)*Math.pow(10,t2-t1);
    },

    round: function(num,n){
        n=n||2;
        if(isNaN(num)||num=="") return 0;
        return Math.round(num*Math.pow(10,n))/Math.pow(10,n);
    }
};
window.QiDoubleUtils = new DoubleUtils();